1. Field of the Invention
The present invention relates to a disposable diaper which includes a top sheet, a back sheet, and an absorber and in which a skin contact sheet is disposed above the top sheet.
2. Description of the Related Art
In recent years, as a diaper for an infant or an elder or disabled person, there has been widely used a disposable diaper which includes an absorber, a top sheet disposed to cover the upper surface of the absorber and at least partially formed of a liquid permeable material, and a back sheet disposed to cover the lower surface of the absorber and formed of a liquid impermeable material. This disposable diaper is used in such a manner that a surface of the top sheet is applied to contact the skin of a wearer of the disposable diaper. Thereby, the urine discharged by the wearer penetrates through the top sheet and is absorbed and retained by the absorber. Further, the back sheet having good leakage preventing performance prevents the leakage of the excrement to the outside of the diaper.
In the disposable diaper of the above-described structure, however, the urine penetrates through the top sheet but most of the stool does not penetrate through the top sheet and thus remains thereon. The stool remaining on the top sheet adheres to the crotch or the buttocks of the wearer. This requires a troublesome wiping work, which increases the burden of child rearing or nursing care and causes skin trouble to the wearer. Such phenomenon becomes more prominent when the stool discharged by the wearer is an unformed stool.
In view of this, another type of disposable diapers has been proposed in which another sheet member (hereinafter referred to as a “skin contact sheet” in the present specification) is disposed above the top sheet (see Paragraph 0010 and FIG. 2 of Japanese Registered Utility Model No. 2559050, and Paragraph 0020 and FIG. 1 of Japanese Unexamined Patent Application Publication No. 2002-11044, for example). These disposable diapers are structured such that the skin contact sheet is formed with an opening capable of passing a stool therethrough (i.e., a stool passing opening) for causing the stool discharged by the wearer to drop on the top sheet through the opening.
According to the above-described disposable diaper, the skin contact sheet first contacts the skin of the wearer. Thus, the top sheet disposed under the skin contact sheet does not easily come into direct contact with the skin of the wearer. That is, the skin of the wearer is separated from the top sheet. This also means that a shielding layer, i.e., the skin contact sheet intervenes between the top sheet and the skin of the wearer. Therefore, even if the stool remains on the top sheet, the effect of substantially decreasing the chance of direct contact of the stool with the skin of the wearer can be expected.
Usually, for such purposes as improvement of the close contact of the skin contact sheet with the skin of the wearer, the skin contact sheet is provided with a stretchable elastic member to form a stretchable region. Thus, the stretchable region is usually formed with a wavy gather by the stretchable elastic member. When pressed against the skin of the wearer, the thus formed gather causes uncomfortable feeling or pain to the wearer in some cases. In particular, in the case of a disposable diaper having the skin contact sheet formed with two openings (i.e., a stool passing opening and a urine passing opening), a region of the skin contact sheet corresponding to a crotch part and sandwiched between the two openings is strongly pressed by or frequently rubbed against the wearer. With the formation of the gather, therefore, the above-described pain or the like and the skin trouble tend to occur in this region. In this regard, the conventional disposable diaper is not satisfactory enough and still open to improvement.